In order to improve the comprehensive utilization of industrial solid waste such as iron tailings and desulfurization ash, sodium hydroxide and calcium sulfate were used as composite excitant, and iron tailings powder, desulfurization ash and slag powder were used as raw materials to prepare iron tailings powder-desulfurization ash cementitious material. The orthogonal test was carried out to analyze the effects of iron tailings powder content, desulfurization ash content, sodium hydroxide content and calcium sulfate content on the compressive strength of the cementitious material and the mix proportion was optimized. The microstructure was characterized by X-ray diffractometer (XRD) and scanning electron microscope (SEM). The results show that the content of sodium hydroxide, iron tailings powder and calcium sulfate has the most significant effects on the 3 d, 7 d, and 28 d compressive strength of the cementitious material, respectively. The optimal content of iron tailings powder, desulfurization ash, sodium hydroxide and calcium sulfate are 20%, 10%, 1% and 9% (mass fraction), respectively. Meanwhile, the 3 d compressive strength of cementitious material is 4.59 MPa, and the 28 d compressive strength is 18.44 MPa, with a dense microstructure and the highest macroscopic strength.